JPH0526384Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a gasket used for high-pressure gas seals, cooling water, lubricating oil seals, etc. in internal combustion engines.

BACKGROUND ART Conventionally, this type of gasket has a cylinder hole B, a water hole, an oil hole C, a tightening bolt hole D, etc. in a gasket sheet body A for attachment to a cylinder head of an internal combustion engine, as shown in FIG. 4, for example. It is installed in a predetermined position.

In this type of gasket, by using a thermoplastic resin such as polyphenylene sulfide (PPS) or polyethylene terephthalate (PET), which has excellent strength, heat resistance, chemical resistance, and dimensional stability, to form the sheet body, it is possible to easily form shapes in which the thickness of each part of the gasket is varied, and to form a surface pressure distribution that satisfies the sealing function.

However, when the gasket sheet main body A is simply provided with tightening bolt holes D as shown in Fig. 5, the tightening load applied locally near the tightening bolt hole opening D may cause the gasket to become thermoplastic depending on the conditions of the operating temperature environment. The pressure limit of the resin itself is exceeded, creep increases, and especially the sealing function is significantly reduced.

Problem to be solved by the invention Therefore, as shown in Fig. 6, tightening bolt hole D
An attempt was made to solve the above problem by fitting the collar E into the inner peripheral surface of the holder.

However, since the amount of compression of the resin body is small (e.g. 5/1000 to 1/100 mm), it is necessary to strictly control the difference between the resin thickness and the height of the reinforcing material in order to ensure sufficient load at the sealing part. There is.

This level difference is about 1/100 to 5/100 mm, and for example, if it deviates from this range, the load may not be distributed to the main body, or conversely, creep may increase excessively due to excessive load on the main body, making it difficult to maintain balance. The problem is that it is difficult to manage.

Means to Solve the Problem This idea reduces the thickness of the entire resin part in the overloaded part of the thermoplastic resin gasket and constrains it in a direction parallel to the sealing surface, thereby reducing the volume change and increasing the volume of the resin. The purpose is to suppress flow and reduce creep.

In order to solve the above-mentioned problems, this invention has a gasket made of a thermoplastic resin with excellent heat resistance such as polyphenylene sulfide or polyethylene terephthalate, and is attached to the lower part of the opening of the tightening bolt hole in the gasket body parallel to the sealing surface. A reinforcing member made of a cylindrical body with a flange was fitted to restrict the flow.

Function A reinforcing material made of a hard material such as metal with a special shape is provided near the opening of the tightening bolt hole in the gasket sheet body made of thermoplastic resin to restrain changes in the volume of the gasket and reduce the volume of the resin itself. This restricts the flow in the direction parallel to the sealing surface, thereby significantly improving the compression creep resistance of the same area.

Embodiment An embodiment of this invention will be described with reference to the drawings. FIG. 1 shows an enlarged longitudinal sectional view of a portion corresponding to the A-A sectional view of the tightening bolt hole of the gasket shown in FIG. 4, and shows the tightening bolt hole of the gasket sheet main body 1 made of thermoplastic resin (PPS) A metal reinforcing member 3 is attached to the inner circumferential surface 2a of 2. This reinforcing material 3 is made of a cylindrical body with a flange, and the cylindrical body part 3a is provided on the inner circumferential surface 2a of the tightening bolt hole 2, and the flange part 3
b is buried in the lower end peripheral edge 2b of the bolt hole so as to form the same plane.

FIG. 2 shows another embodiment, in which an edge 3c of a flange portion 3b of a cylindrical body with a flange having the same shape as the metal reinforcing member of the first embodiment is erected, and the edge 3c is inserted into the gasket sheet body 1. Construct into an internal shape.

FIG. 3 shows another embodiment in which one end 4a of a metal reinforcing member 4 having a Z-shaped cross-section protrudes from the lower edge of the bolt hole 2, and the other end 4b is connected to the gasket sheet main body 1.
Construct into an internal shape.

In addition, when the elastic modulus of the metal reinforcing material and the thermoplastic resin that makes up the sheet body is E1 and E2,
If E2/E1 = 1/100 to 1/1000, the load sharing ratio is effective when the thickness of the reinforcing material is 1/2T to 9/10T with respect to the thickness T of the thermoplastic resin gasket sheet body.
2/3T to 4/5T is desirable.

Effects of the device As mentioned above, this device places a metal reinforcing material near the opening of the tightening bolt hole so as to restrict the flow in the direction parallel to the sealing surface. At the same time, the flow of the gasket sheet body made of thermoplastic resin during hot heating is geometrically restrained, and at the same time, the insertion part has a larger proportion than the case of thermoplastic resin alone, assuming the total tightening load is constant. By sharing the load, the load on the resin itself can be reduced.

In addition, the overall thickness of the resin part in the overloaded part of the thermoplastic resin gasket is made thinner, and the sealing surface is restrained in a direction parallel to the sealing surface, thereby reducing volume change, suppressing resin flow, and reducing creep. be able to.

Regarding gaskets formed using thermoplastic resin, the respective creep characteristics ( Assuming that the thicknesses of the reinforcing materials in Y and Z are equal, as shown in FIG. 7, the gasket Z of the present invention can reduce the variation in creep characteristics compared to the conventional gasket Y.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention; FIG. 1 is an enlarged vertical cross-sectional view taken along line A-A in FIG. 4, which will be described later; FIGS. 4 is a front view of a conventional gasket, FIG. 5 is an enlarged longitudinal sectional view of the conventional gasket taken along line A-A in FIG. 4, and FIG. 6 is another conventional gasket. An enlarged sectional view of the A-A line section in FIG. 4 of the example,
FIG. 7 is a diagram showing the creep characteristics of the gasket of this invention and the conventional gasket. 1... Gasket sheet, 2... Tightening bolt hole, 2a... Inner circumferential surface, 2b... Lower end periphery, 3
...Metal reinforcing material, 3a...Cylindrical body part, 3b...Brim part, 3c...Brim part edge, 4...Metal reinforcing material,
4a...one end, 4b...other end.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A reinforcing material consisting of a cylindrical body with a flange attached to the lower part of the tightening bolt hole of the gasket sheet body made of a thermoplastic resin with excellent heat resistance such as polyphenylene sulfide or polyethylene terephthalate. The cylindrical part of the reinforcing material is brought into contact with the lower inner circumferential surface of the tightening bolt hole, and the collar part is embedded in the lower peripheral edge of the bolt hole so as to form the same plane. gasket. 2. A gasket characterized in that the edge of the flange portion of the reinforcing material according to claim 1 is internal to the gasket sheet main body.